1. Field Of The Invention
This invention relates in general to the field of cooling integrated circuits and, in particular, to the field of providing a system for conducting heat away from the body and leads of integrated circuits.
2. Description Of Related Art
Efforts at the thermal management of electronic devices are old and well known, as are the adverse effects of excessive temperatures on the performance and integrity of such devices.
Early attempts to control and dissipate heat generated by or around electronic devices included air ventilation apparatuses such as fans to pull ambient air into and exhaust it from a cabinet or chassis containing heat-generating electronic devices. A variety of passive cooling techniques have more recently been employed with semiconductor devices to dissipate heat produced by them. These techniques have included: mica pads; silicone grease; the use of mechanical heat sinks with cooling fins; such heat sinks with a bag of thermally conductive fluid; thermoelectrically cooled devices; ceramic-slab metal-plate composite heat sinks; and thermally conductive elastomeric blankets, to name a few.
Thermal interface materials for removing heat from electronic devices are described in "CHO-THERM.RTM. Thermal Interface Materials," Chomerics, Inc. These products include either a silicone or urethane elastomer binder with boron nitride, magnesium oxide or aluminum oxide as a thermally conductive filler and a reinforcement made from fiberglass cloth or a polyimide or polyester film. These products are electrically non-conductive. In one prior art method of thermal management of heat produced by an integrated circuit, the heat flows from the integrated circuit to a blanket of a thermally conductive elastomer disposed on the integrated circuit and then to a mechanical finned metal heat sink disposed on the blanket.
U.S. Pat. No. 5,006,924 discloses a heat sink for use with high density integrated circuit substrates which includes a compliant bag containing thermally conductive fluid disposed adjacent a typical finned heat sink. The bags rest on the tops of the integrated circuits. A pump may be utilized to circulate fluid through a plurality of interconnected bags.
U.S. Pat. No. 5,012,324 discloses a heat sink body for use with electronic power components which has a ceramic slab covered on both sides with metal plates.
U.S. Pat. No. 5,012,325 discloses a thermoelectrically cooled integrated circuit package.
U.S. Pat. No. 5,006,925 discloses a three-dimensional electronic chip package with a plurality of semiconductor device substrates and a cooling channel through the package for circulation of a cooling fluid therethrough.
U.S. Pat. No. 5,014,161 discloses an elastomeric matrix with conductive elements embedded therein which contact conductive contact pads which in turn contact semiconductor devices.
U.S. Pat. No. 5,010,386 discloses an insulator-separated vertical complementary semiconductor device having an insulating layer.
U.S. Pat. No. 5,006,923 discloses a substrate for mounting integrated circuits in which a non-conductive sealing glass frit covers the integrated circuits.
Although each of the prior art techniques result in some heat transfer from the protected electronic devices, it is desirable to increase the amount of heat transferred from integrated circuits (and to increase the rate of this transfer). It is also desirable to accomplish this in an effective manner which does not substantially increase the overall size of apparatuses employing integrated circuits. Finally, it is desirable to accomplish this with relatively simple materials which are readily available and easy to work with.